Release device for torque wrenches



Sept. 28, 1954 H. c. PEDERsEN 2,690,090

RELEASE DEVICE FOR ToRQUE WRENCHES Filed July 14, 1952 2 Sheets-Sheet l I' .1. f4 9,0 f f' l;

I' :g5-5:11: :c55-53;): 7 Egg-' W l N32 :l Ja 15! f' 2 r. l

0 l 7 zal V03 I f f i W .a L I ;L E z 11's 94: /M Il -98 I l 4.5 I I l l' gz I l e 46 l 7a4 I: I l 42 l 56 fr" z E8 '-.f

ATTORNEYS Sept. 28T-1954 H. C. PEDERSEN RELEASE DEVICE FOR TORQUE WRENCHES 2 Sheets-Sheet 2 Filed July 14, 1952 l ).Z a- Pedesem '.l; ATTORNEYS.

Patented Sept. 28, 1954 UNITED STATES PATENT oFEicE 2,690,090 RELEASE DEVICE FOR TORQUE WRENCHES Harry C. Pedersen, Royal Oak, Mich., assignor to Clyde Engineering and Manufacturing Corporation, a corporation ofk Michigan Application July 14, 1952, Serial No. 298,659

4 Claims.

This invention relates to a release device for a torque wrench and more particularly to a release mechanism for a torque wrench of the type disclosed in my co-pending application Serial No. 130,287 since matured into Patent No. 2,634,640, dated April 14, 1953, in which the driving teeth for the drive shaft of the wrench socket are moved out of engagement withone another and held in such position by the engagement of a roller with a skirt carried by the shaft driving head.

Wrenches of the type to which this invention relates are power driven mounted in multiple, and are so adjusted that when the resistance of a screw nut or bolt to turning attains a predetermined value, the driving teeth are disengaged from one another so that despite the continuous operation of the primeY mover, no further torque will be applied to the screw nut or bolt.

Wrenches of this type have found wide use on production lines, and at times,I usually due to faulty lubrication the collar carrying the driving teeth has failed to snap back into driving relation with the wrench shaft driving head, with the result that the wrench would not function and faulty production would result.

The primary object of this invention is to positively assure the meshing of the driving teeth and head about the axis of the shaft under the iniuence of the spring which determines the degree of resistance required to throw the wrench into inoperative position.

Among its features the invention embodies forming in each recess in the driving head a shoulder adjacent the side of the recess which is engaged by a roller, a stop lug carried by the sleeve for engagement with the shoulder to positively hold the parts separated, and lingers carried by the sleeve and movable longitudinally thereof for engaging the shoulders and establishing relative rotation between the sleeve an driving head of a magnitude sumcient to cause the skirt of the driving head to move along the surface of an adjacent roller under the influence 2 of the spring which holds the teeth of the sleeve and driving head in mesh.

In the drawings,

Fig. 1 is a longitudinal sectional View through the drive housing and casing of a torque wrench embodying the features of this invention, showing the Wrench in operative position therein,

Fig. 2 is a transverse sectional view taken suhstantially along the line 2 2 of Fig. 1,

Fig. 3 is a transverse sectional View taken substantially along the line 3 3 of Fig. l,

Fig. 4 is a side view partially in section of the wrench portion of the device showing the casing removed and the driving teeth of the sleeve and driving head separated,

Fig. 5 is a vertical sectional View through the structure illustrated in Fig. 4 showing the driving teeth in cooperative relation,

Fig. 6 is a fragmentary side view of the sleeve and driving head showing the parts in their separated positions, and

Fig. 7 is a view similar to Fig. 6 illustrating a release linger moving the sleeve and head about their common axis to bring the curved surfaces of the rollers into active contact with the curved cam surfaces on the skirts to cause the parts to snap back into operative position under the iniluence of the torque-regulating spring.

Referring to the drawings in detail a housing I0 enclosing a prime mover (not shown) has mounted therein an anti-friction bearing I2 in which one endof the drive shaft i4 of the prime mover is mounted to rotate. Carried by the shaft lli adjacent the anti-friction bearing l2 is a pinion I6 the purpose ofwwhich will hereinafter appear. of the anti-friction bearing I2 and extending parallel to the axis thereof is an opening i8 in which is seated an anti-friction bearing 20. A stem 22 is mounted in the anti-friction bearing Eiland carries at the end thereof on the exterior of the housing a head 2i carrying on its end Van annular row of circumferentially spaced teeth 26 having gently inclined cam surfaces 23 therebetween. A gear 30 is nxed to the stem 22 within the housing It and this gear meshes with the pinion I6 so that when the prime mover is set into operation the head 24 will be rotated. Opening through the end of the head 24 remote :from the stem 22 and extending axially through the head andinto the stem is a bore 32 the purpose of which `will hereinafter appear.

Secured to the housing in concentric relation to the opening I8 and encircling the head 24 is an elongated tubular casing 34 having adjacent v 50 to yieldingly its end opposite the housing I6 an internally extending annular flange 36 and formed within the casing 34 in longitudinally spaced relation lto the flange 36 are longitudinally spaced annular grooves 33 and 40 for the reception of expanding split rings 42 and 43 which form stops the purpose of which will hereinafter appear.

Entering the bore 32 for rotation and longitudinal movement relative to the head 24 and stein 22 is the pilot spindle 5U of a head 52 carrying adjacent the pilot spindle 58 an anti-friction bearing 54. The end of the head 52 remote from the pilot spindle is recessed as at 56 and carries on the end thereof remote from the pilot spindle an annular row of circumferentially spaced teeth 58 having cam surfaces 60 therebetween which are relatively steep and lie at angles reverse to the angles of the cam surfaces 28. A shaft 62 enters the recess 56 and is xed to the head 52 for rotation therewith and this shaft extends axially from the head in a direction opposite the pilot spindle 50 and in axial alignment therewith. The shaft 62 is provided adjacent the end thereof remote from the head 52 with external screw threads 64 and carries an axial extension 66 for engagement with a wrench socket.

Mounted on the anti-friction bearing 54 carried by the head 52 is a collar 10 carrying at the end adjacent the pilot spindle 58 an annular row of circumferentially spaced teeth 12 which are adapted during certain conditions of the operation of the wrench to engage the teeth 26 and effect driving connection between the head 24 and collar 18. Extending between the teeth 12 on the collar are cam the teeth 26 and 12 are engaged are in abutting relation to the cam surfaces 28. Carried by the end of the collar 10 and extending longitudinally from the end thereof remote from the teeth 12 is an annular ange or skirt 13 having extending therethrough and opening through the end thereof remote from the teeth 12 peripherally spaced recesses 16 and the corner of each recess 18 adjacent one side thereof is curved to form a cam surface 19 which merges into the adjacent edge of the flange or skirt, as will be readily understood upon reference to Figures 6 and '1.

A sleeve 8D is mounted on the shaft 62 adjacent the collar 16 and carried by the end of the sleeve 86 adjacent the head 52 is an annular row of peripherally spaced teeth 82 which under normal operation of the wrench mesh with the teeth 58 carried by the head 52. Relatively steep cam faces 84 extend between the teeth 82 and during the normal operation of the wrench frictional engagement of the cam faces 80 of the head 52 with the cam faces of the sleeve 84 is maintained by a relatively stiff spring as will hereinafter be explained. Threaded on the threads 64 of the shaft 62 is a nut 86 and surrounding tne shaft 62 and abutting the nut 86 and sleeve 80 is a relatively stiff compression coiled spring 88 which yieldingly urges the cam faces 84 into frictional contact with the cam faces 60 and the teeth 82 and 58 into mesh. A relatively light coiled spring 90 is seated on the inner end of the bore 32 and engages the inner end of the pilot spindle hold the -driving teeth 26 and 12 out of mesh.

The wrench so far described will serve admirably in arresting further turning movement on a screw, nut or bolt when the resistance to turning by the screw, nut or bolt attains a predetermined value, and the value of such resistance can be readily regulated by turning the nut surfaces 14 which when 4 86 to increase or decrease the eort of the spring 88.

In order to prevent wear on the points of the teeth 58 and 82 the sleeve 88 is provided at the end thereof carrying the teeth 82 with an annular longitudinally extending skirt 92 having formed therein and opening through the end thereof remote from the sleeve a group of circumferentially spaced recesses 94 in which are received the portions of the skirt 13 of the collar 10 between the recesses 16 therein. Formed in the corner of each recess 94 adjacent the side thereof nearest the high points of the teeth 82 is an arcuate recess 95. A roller 98 of hardened steel is seated in each wrench is in normal operation with the teeth 82 of the sleeve 88 in mesh with the teeth 58 of the head 52, the rollers 98 are accommodated in the recesses 16 below the shoulders 18. See Fig. l.

When however, the resistance to turning of the shaft 62 attains a predetermined value the cam faces 6|) will ride on the cam faces 84 and cause the sleeve to separate from the head or collar 52 against the effort of the spring 88. The relative rotation of the parts will cause the rollers 98 to ride along the curved cam surfaces 19 as suggested in Fig. 1 until the rollers 98 rest thereon adjacent the flat end portions of the skirt 13 as shown in Fig. 6. Thus the engagement of the rollers 98 with curved end portions of the skirt 13 will hold the teeth 58 and 82 out of mesh so as to avoid Wear on the points thereof until the wrench is withdrawn from the work and the shaft 62 is free to turn at which time the faces of the rollers will move on the inclined portions of the curved cam faces 19 and under the influence of the spring 88 restore the device to working condition.

The structure so far described serves admirably in freeing the shaft 62 from turning by the prime mover and preventing wear on the points of the teeth 58 and 82 but at times, usually due to faulty lubrication, the sleeve 89 will remain separated from the driving head or collar 52 so that when the device is withdrawn from the work, the rollers 98 will fail to move along the curved cam faces 19 and thus destroy the function of the wrench for the next operation.

In order to overcome this dilculty and eifect positive rotation of the sleeve 89 relative to the driving head or collar 52 a shoulder 18 is provided in each recess 16 adjacent each curved cam face 19 on the skirtr13 and each shoulder is provided with a curved outer corner 11 for a purpose to be more fully hereinafter described. Mounted on the sleeve 89 for longitudinal sliding movement between the stop rings 42 and 48 of the casing 64 is a ring or collar 44 having in its inner face an annular groove 46 and an enlarged bore 48. Formed in the skirt 92 of the sleeve 88 between the recesses 94 therein are peripherally spaced grooves |99 and mounted for longitudinal sliding movement in said grooves |98 are fingers |92. Lugs |84 are carried by the ngers |92 and are received in the groove 46 of the ring or collar 44 so that as the ring or collar 44 moves longitudinally on the sleeve 88, the fingers |88 will likewise move relative to the sleeve. The ends of the fingers |92 remote from the lugs |94 project into the recesses 16 in the skirt 13 of the driving head 52 and are rounded as at |08 to form earn faces which under certain circumstances engage the rounded corners 19 to establish positive relative rotation between the sleeve 88 and driving head 52 to move the rollers 98 along the curved cam recess 98 and when the ring 42 is spaced longitudinally from the ring or collar iii and the teeth 58 and 84 are being held ing 80 will move longitudinally relative to the inner assembly including the sleeve 6G, driving head 52 and shaft 62 so as to bring the stop ring 42 into engagement with the ring or collar 44 to 89 and driving head 52 in a direction to move the rollers 98 into a position Where they will ride on the curved portions i9 of the skirt 'i3 under the iniiuence of the spring 88. By thus positively establishing initial rotary motion between the driving head 52 and sleeve 80 the positive restoration of the driving connection between the sleeve 89 and shaft E52 is accomplished and all danger of failure of the wrench is eliminated.

While in the foregoing there has been shown and described the preferred embodiment of this to Without departing from the spirit and scope of the invention as claimed.

What is claimed is:

fingers for engaging the other Clutch member and establishing relative rotation between the clutch members, and means carried by the ngers and member.

3. The subject matter recited in claim 2 in clutch members separated, means for positively releasing the clutch member holding means com- References Cited in the le of this patent UNITED STATES PATENTS 

